As an autosomal dominant transmitted disease, FH naturally occurs in two forms: homozygous and heterozygous. As noted in textbooks since time immemorial, FH homozygotes are rare and their frequency in the general population is about 1:1,000,000. The incidence of heterozygotes has long been cited as 1:500, but this number is currently being corrected and is more frequently reported as a range of either 1:200 to 1:500, or 1:300 to 1:500.
We will try to be more specific and provide data in more detail. First, it must be said that there are significant differences among various populations. The population in the former Czechoslovakia was relatively homogeneous and, in terms of daily practice, Czech and Slovak physicians did not need as much data on the incidence of various diseases in other countries and populations, but that is no longer the case. In today’s globalized world, physicians encounter patients of various origins and must, therefore, be aware of the differences among various populations.
In the case of FH, the “founder effect” (i.e. increased frequency of FH or a predominant mutation in a specific population because a new population was founded by a very small subset of the original population “bottle necking”) is an essential factor in population differentials. It has a clear influence on the incidence of FH homozygotes and FH heterozygotes. The population incidence of FH homozygotes based on the founder effect is between 1:10,000 and 1:100,000. The highest incidence rates are found in the Afrikaner population in South Africa (1:10,000), and high rates have also observed in French Canadians (mainly from the province of Quebec). In Europe, the highest incidence is in northwestern Europe. With regards to heterozygotes, the highest incidences are (again) found in the Afrikaner population in South Africa (as high as 1:70) and in French Canadians (1:270). The Netherlands reports an incidence of 1:300-400. With regard to the Czech population (which is similar to the American population), the more commonly cited heterozygote incidence of 1:500 is still valid. There are other populations with a higher incidence of FH that have not yet been precisely specified via epidemiological investigation (e.g. Lithuanian Jews, and the Lebanese).
When examining the EAS Consensus Statement, one can see enormous differences between individual countries that cannot be explained by economic conditions or the quality of the health care system.
It is evident that a country with a state supported FH research project (Netherlands) has an incredible advantage, which has resulted in the identification of over 70% of FH patients.